Some patients suffer from various conditions which require at least a portion of an ankle joint to be effectively immobilized. Such conditions include severe arthritis, infection and/or avascular necrosis of one or more bones in the region, congenital deformity of the tibio-talar or talocalcaneal joint or certain types of neuropathy. In all of these conditions, any motion of the bones relative to each other can cause severe pain in the foot or ankle to a point where a patient becomes effectively unable to walk or put any pressure on that foot. Accordingly, immobilization of the ankle joint becomes an option for the patient to begin walking without excruciating pain in the ankle and foot.
Immobilization of an ankle joint is usually done by inserting one or more rigid rods or pins into one or more bones in the ankle and in the hindfoot portion of the foot. This permanently affixes certain bones to other bones. The medical term for this type of permanent bone fixation is ankle arthrodesis. In a normal ankle joint, because of the placement of the bones, a straight rod which passes vertically through the calcaneus and into the tibia will normally pass through the talus.